Abstract
It is well known observation that farms contaminated with Aleutian Disease (AD) virus on an average have a lower breeding result than not infected farms. In the Danish eradication programme a farm may be registered as an A-farm, if a number of conditions are fullfilled. Among the conditions are yearly testings by countercurrent immuno-electrophoresis of all breeders or certain groups of these. The testing is carried out by the laboratory of the Danish Fur Breeder’s Association. Starting with the testing of 30.000 samples in 1976 the number of tests were 2.9 millions in 1986. The number of A-farms was more than 1,500 out of 4236 in 1986. The A-farms had in 1986 608,116 breeders with an average breeding result of 4.81 compared to the not tested farms that have an average of 4.37 kits per mated female. While the number of breeders has increased from 1.0 million in 1980 to 2.1 million in 1986, the percentage of infertile females has in the same period decreased from 14.7 to 10.9 with an average breeding result increasing from 4.09 to 4.69 (Anon. 1986).